Comment 4 for bug 1782444

Due to intentional change to tighten permissions: https://github.com/openstack/charms.openstack/commit/51d00c45e2e3b1f25513ce4f90f35007bac15fc9

Add properties to the class to resolve:

class MyCharm(charms_openstack.charm.OpenStackCharm):
    user = 'myuser'
    group = 'mygroup'

For charms that use modwisgi also change the user/group in the WSGI setup similar to:
https://github.com/openstack/charm-gnocchi/commit/bc1745115b6a9c7837075a4353d60a1e5a1e2ca9